Note: It isn't possible to generate
a URL that points to the private library of another
site.

dw.io.File

File access to all libraries, folders, and content,
for example:

LIBRARIES/[Library
Name](/...)

B2C Commerce uses a
fall-back mechanism to determine the site library path. It first
checks to see if the token represents the ID of a site in B2C Commerce. If it does, it constructs a file path within the
private library of that site. If the token isn't the ID of a
site, then B2C Commerce interprets it as the ID of a shared
library within B2C Commerce. You can use this mechanism to
construct file paths for private and shared libraries (as long
as there are no naming conflicts).

Pipelets

These pipelets support both private and
shared libraries: GetContent, ImportContent, and
ExportContent